Image by Keith McDuffee
By Kathee Mierzejewski
A lot of people enjoy having small kitchen window sill plants like rosemary. However, although they are easy to grow, they are not without faults. Oftentimes, you will find that there are problems with growing rosemary, one of them being a common fungus.
Powdery Mildew on Rosemary
Perhaps you have noticed a white powder on your rosemary plants in your kitchen. If so, you are not alone. The white powder is actually powdery mildew on rosemary, a common plant ailment. It is caused by many different fungi that are closely related. This is one of the most common problems with growing rosemary plants, and all indoor plants actually. Each indoor plant has a white powdery mildew that is specific to that particular plant. Rosemary is no different.
Powdery mildew won’t kill the rosemary plant, but it will weaken it. This is one of the easiest plant diseases to diagnose. Powdery mildew appears as a white powder on rosemary, which coats the leaves of the plant. The powder is actually thousands of little spores and can spread to other plants if severe enough.
How to Get Rid of Powdery Mildew on Rosemary
Powdery mildew can be partially removed if you rub the leaves of your rosemary plant carefully. If you don’t try to remove some of it, the white powder on rosemary can result in leaf drop. The powdery mildew on rosemary can rob the plants of the nutrients they need to grow.
Powdery mildew on rosemary is one of the most common problems with growing rosemary in the house. It can definitely make the plant look a little ragged, but it shouldn’t kill it. You should pick up any infected leaves that have fallen off the plant. Also, take infected plants out of high humidity rooms, like the bathroom or kitchen.
Finally, spraying the white powder on rosemary with a fungicide will help to kill it. You might want to try spraying water on it first every few days to knock the mildew off before resorting to fungicide. You might need to repeat this every few days for it to be effective, but be careful not to overwater the plant itself or you will end up with root rot, another one of the common problems for rosemary plants or other indoor houseplants.
Now that you know what the white powder on rosemary is, and how to treat it, you can go back to enjoying your rosemary plant.